Drug interactions
Erlotinib + Idelalisib
Severity: Major
Erlotinib and Idelalisib: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Idelalisib is a strong CYP3A4 inhibitor and is expected to substantially raise erlotinib concentrations. This increases the risk of erlotinib toxicity including severe rash, diarrhea and lung toxicity.
What this interaction means in plain words
Erlotinib and Idelalisib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Erlotinib belongs to Oncology; Idelalisib belongs to Oncology.
Why it happens
Strong inhibition of CYP3A4 metabolism of erlotinib by idelalisib.
What to do
Avoid the combination where possible. If it is necessary, monitor closely and reduce the erlotinib dose in 50 mg steps for severe toxicity.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Erlotinib
- Amobarbital + Erlotinib Major
- Apalutamide + Erlotinib Major
- Carbamazepine + Erlotinib Major
- Cobicistat + Erlotinib Major
- Darunavir + Erlotinib Major
- Dexlansoprazole + Erlotinib Major
Other interactions of Idelalisib
- Alfuzosin + Idelalisib Contraindicated
- Cisapride + Idelalisib Contraindicated
- Dihydroergotamine + Idelalisib Contraindicated
- Dronedarone + Idelalisib Contraindicated
- Eletriptan + Idelalisib Contraindicated
- Eplerenone + Idelalisib Contraindicated
Frequently asked questions
Can I take Erlotinib with Idelalisib?
MediHelp rates the interaction as major. Erlotinib and Idelalisib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Idelalisib is a strong CYP3A4 inhibitor and is expected to substantially raise erlotinib concentrations. This increases the risk of erlotinib toxicity including severe rash, diarrhea and lung toxicity.
How serious is the interaction between Erlotinib and Idelalisib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible. If it is necessary, monitor closely and reduce the erlotinib dose in 50 mg steps for severe toxicity.
What other medicines interact with Erlotinib?
MediHelp also lists interactions of Erlotinib with, for example, Amobarbital, Apalutamide, Carbamazepine. The full list is on the Erlotinib page.
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